Jo Cals, Dutch lawyer and politician, Prime Minister of the Netherlands (b. 1914)
Jozef Maria Laurens Theo "Jo" Cals (18 July 1914 – 30 December 1971) was a Dutch politician of the defunct Catholic People's Party (KVP) now the Christian Democratic Appeal (CDA) party and jurist who served as Prime Minister of the Netherlands from 14 April 1965 until 22 November 1966.Cals studied law at the Radboud University Nijmegen obtaining a Master of Laws degree and worked as a lawyer and prosecutor in Nijmegen from November 1940 until August 1948 and as researcher at his alma mater from February 1941 until May 1949. Cals also worked as a legal and economics teacher in Roermond from October 1943 until June 1945. Cals became a Member of the House of Representatives shortly after election of 1948 taking office on 19 August 1948 serving as a frontbencher and spokesperson for Education and Social Work. Following a cabinet reshuffle he was appointed as State Secretary for Education, Arts and Sciences in the Cabinet Drees–Van Schaik taking office on 15 March 1950. The Cabinet Drees–Van Schaik fell on 24 January 1951 and was replaced by Cabinet Drees I with Cals continuing his office. After the election of 1952 Cals was appointed as Minister of Education, Arts and Sciences in the Cabinet Drees II taking office on 2 September 1952. After the election of 1956 Cals retained his position in the Cabinet Drees III. The Cabinet Drees III fell on 11 December 1958 and was replaced by the caretaker Cabinet Beel II with Cals continuing his function. After the election of 1959 Cals once again retained his office in the Cabinet De Quay. After the election of 1963 Cals wasn't offered a cabinet post in the new cabinet and returned to the House of Representatives on 2 July 1963 serving as a frontbencher and spokesperson for the Interior and Kingdom Relations. Cals also became active in the public sector as a non-profit director and served on several state commissions and councils on behalf of the government.

After the fall of Cabinet Marijnen Cals was asked to lead a new cabinet. Following a successful cabinet formation Cals formed the Cabinet Cals and became Prime Minister of the Netherlands taking office on 14 April 1965. The cabinet fell just one year into its term after a major political crisis and following a difficult cabinet formation wasn't included in a new cabinet. Cals left office following the installation of the caretaker Cabinet Zijlstra on 22 November 1966 and announced his retirement.

Cals semi-retired from active politics at just 52 and became active in the private and public sectors as a corporate and non-profit director, and served as a diplomat and lobbyist for several economic delegations and presided over several state commissions and councils for the government. Cals was known for his abilities as a efficient manager and his work ethics. During his premiership, his cabinet were responsible for major social reforms to social security, closing the mines in Limburg and stimulating Urban development in the Randstad. Cals was granted the honorary title of Minister of State on 5 December 1966 and continued to comment on political affairs as a statesman until he was diagnosed with a terminal brain tumor and died in December 1971 at the age of just 57. He holds the distinction of as the fourth longest-serving cabinet member since 1850 with 14 years and 353 days and his premiership is consistently considered both by scholars and the public to have been average.